JPH04110806A - Optical fiber, optical fiber array and production thereof - Google Patents

Abstract

PURPOSE:To facilitate the holding of optical fibers by forming longitudinal projecting lines for holding a posture which have a section exclusive of a circular shape and have angle parts in the section thereof on the outer peripheral surface. CONSTITUTION:The optical fiber 1 is put into a hollow groove 4a and the space between the optical fiber 1 and the hollow groove 4a is filled with a UV curing resin. While the part above the optical fiber is pressed by a glass substrate 5, the resin is irradiated with UV rays and is thereby cured. The optical fiber 1 is taken out of the hollow groove 4a of an Si substrate 4 after curing and the optical fiber integrally formed with the projecting lines 2 for holding the posture on the outer peripheral surface is obtd. The projecting lines 1 are placed along the inside wall of the holding groove 7a, by which the polarization maintaining directions of plural pieces of the optical fibers are unified in one direction. An LiNbO3 substrate 6 is put on the optical fibers 1 to press the optical fibers. The UV curing resin is cured, by which the optical fiber array constituted of the polarization maintaining optical fibers uniformed in the polarization maintaining direction is obtd.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to optical fibers, optical fiber arrays, and methods of manufacturing them.

Conventional technology and its problems Optical devices such as optical switches that have optical waveguides formed on a substrate as a component require an optical fiber array to input light into or output light from the optical device. It is. Optical fiber arrays require that the optical fibers are aligned in a straight line and that the core spacing of the optical fibers is precisely controlled. Optical fiber arrays using polarization-maintaining optical fibers require that the polarization-maintaining directions be aligned.

An optical fiber array constructed using conventional polarization-maintaining optical fibers has a block formed with a plurality of V-grooves for fixing the optical fibers.

After the optical fibers are arranged in these plurality of V-grooves, the optical fibers are rotated and adjusted before being fixed to match the polarization maintaining direction.

However, when one optical fiber is rotated for adjustment, the adjacent optical fiber also rotates, so it is very difficult to adjust the polarization maintaining direction in an optical fiber array.

SUMMARY OF THE INVENTION OBJECTS OF THE INVENTION The purpose of the invention is to facilitate the retention of optical fibers.

This invention also. It is an object of the present invention to make it possible to manufacture an optical fiber array relatively easily.

Arrangement 1 of the Invention Functions and Effects The optical fiber according to the present invention is characterized in that an attitude-maintaining protrusion having a cross section other than circular is formed along the longitudinal direction on the outer peripheral surface.

It is preferable that the cross section of the posture-maintaining protrusion has a corner.

The method for manufacturing an optical fiber according to the present invention includes preparing a mold having grooves for forming posture-maintaining protrusions, and injecting a liquid material that hardens by energy irradiation between the grooves of the mold and the optical fiber. The present invention is characterized in that the attitude maintaining protrusion is integrally formed on the optical fiber by irradiating energy to harden the liquid material, and then the optical fiber is separated from the mold.

The outer circumferential surface of the optical fiber on which the posture-maintaining protrusions are formed may be the outer circumferential surface of the cladding, or may be the outer circumferential surface of the coating outside the cladding.

Liquid materials that are cured by energy radiation include photocurable or thermosetting resins, such as ultraviolet (UV) cured resins. Examples of inorganic materials include coating liquids for forming thermosetting films.

Liquid state also includes gel state. Other liquid materials that can be cured by energy irradiation include, for example, thermosetting materials. Examples of thermosetting inorganic materials include coating liquids for forming thermosetting films. There are many types of coating liquids, and ZrO2, TiO2,
AN203. A material containing SiO2 or the like is preferable.

According to this invention, since the protrusions for maintaining the posture are formed on the outer circumferential surface of the optical fiber, the posture of the optical fiber having a circular cross section that can easily rotate once can be always maintained constant by the protrusions. When the present invention is applied to a polarization-maintaining optical fiber, the polarization-maintaining direction is made so that the relationship between the polarization-maintaining direction and the above-mentioned ridges is always constant, so that the polarization-maintaining direction can be clearly seen by the above-mentioned ridges, and It becomes possible to easily align the polarization maintaining directions of a plurality of polarization maintaining optical fibers.

The optical fiber array according to the present invention has a plurality of optical fibers formed along the longitudinal direction of a protruding strip for attitude maintenance having a cross section other than a circular shape on the outer circumferential surface, or a plurality of optical fibers having the protruding strip as described above. It is characterized in that they are arranged in a line and fixed in the recesses of a block with suitable recesses.

A plurality of optical fibers may be stacked in one recess, or a plurality of quadrangles may be arranged in a row in the block, with one optical fiber accommodated in each quadrant.

The method for manufacturing an optical fiber array according to the present invention involves creating a plurality of optical fibers each having posture-maintaining protrusions along the longitudinal direction on the outer circumferential surface, and is suitable for holding optical fibers having the above-mentioned protrusions on a block. The optical fibers having the protrusions are arranged in a line and fixed in the concave portion of the block.

An optical fiber having an attitude-maintaining protrusion provided along its longitudinal direction on its outer circumferential surface is held opposite to the above-mentioned groove having a groove for forming the attitude-maintaining protrusion. A liquid material that is hardened by energy irradiation is injected between the optical fiber and the optical fiber, and the liquid material is hardened by irradiating energy.
Thereafter, the optical fiber is manufactured by separating it from the mold.

According to this invention, since the protrusions for posture maintenance are provided along the longitudinal direction on the outer circumferential surface of each of the plurality of optical fibers constituting the optical fiber array, the protrusions are used to connect the plurality of optical fibers. The posture of the optical fiber can be easily kept constant. In particular, in an optical fiber array using polarization-maintaining optical fibers, each polarization-maintaining optical fiber (
If the polarization-maintaining direction of the block and the above-mentioned protrusions are made in advance so that a certain relationship is maintained, optical fibers with uniform polarization-maintaining directions can be created by simply arranging the optical fibers in the recesses of the block.
array can be obtained. It is not necessary to adjust the polarization maintaining direction by rotating the optical fibers after arranging the optical fibers in the recesses of the block as in the conventional method, so it is relatively easy to create optical fibers using polarization maintaining optical fibers.・It becomes possible to manufacture arrays and reduce costs.

DESCRIPTION OF THE EMBODIMENTS FIGS. 1A to 1E show an embodiment of the present invention, which is an example of the manufacturing process of an optical fiber array composed of polarization-maintaining optical fibers. In this embodiment, a PANDA fiber is shown as the polarization maintaining optical fiber.

A Si substrate 4 is prepared, and grooves 4a corresponding to the shape of the attitude-holding protrusions to be formed on the Si substrate 4 are formed by dicing (FIG. 1(A)).

In this embodiment, the groove 48 has a rectangular cross section, and its width is set equal to the diameter of the optical fiber 1.

A UV (ultraviolet) curing resin, which is the material of the posture holding protrusion 2, is injected into the groove 4a of the Si substrate 4, and the groove 4a is
The optical fiber 1 is inserted into the groove 4a, and the space between the optical fiber 1 and the groove 4a is filled with UV curing resin. While holding the top of the optical fiber with the glass substrate 5, UV rays are irradiated from above the glass substrate 5 to harden the UV curing resin (Fig. 1 (B)
).

After the UV curing resin is cured, the optical fiber 1 is taken out from the groove 48 of the S1 substrate 4 (FIG. 1(C)).

As a result, an optical fiber is obtained in which the protruding strip 2 for posture maintenance is integrally formed on the outer circumferential surface. The outer circumferential surface of the optical fiber on which the posture-maintaining protrusions 2 are formed may be a cladding layer or a surrounding coating layer.

By repeating the steps in FIG. 1(B) and FIG. 1(C), a large number of optical fibers 1 having posture-maintaining protrusions 2 formed thereon are obtained. At this time, all the optical fibers are aligned so that the polarization maintaining direction of the optical fiber 1 and the attitude maintaining protrusion 2 have the same positional relationship. Since the optical fibers having the attitude-maintaining protrusions 2 are manufactured one by one, it is relatively easy to align the polarization-maintaining directions.

Next, L i NbO3 substrates 6 and 7 are prepared, and deep holding grooves 7 a having a width equal to the diameter of the optical fibers 1 are formed in one L L Nb 03 substrate 7 so that a plurality of optical fibers 1 can be arranged vertically. is formed by dicing (FIG. 1(D)).

A required number of optical fibers 1 are inserted into the holding groove 7a of the L i N b 03 substrate 7 so that the polarization holding direction is the same. As mentioned above, since there is a constant relationship between the attitude-maintaining protrusion 2 of the optical fiber 1 and the polarization maintaining direction, the protrusion 2
By aligning the optical fibers with the inner wall of the holding groove 7a, the polarization maintaining directions of the plurality of optical fibers are uniformly aligned. At this time, UV curing resin is injected into the holding member 347a. Also,
Cover the LiNbO3 substrate 6 and press down the optical fiber 1. By curing the UV curing resin, an optical fiber array composed of polarization-maintaining optical fibers aligned in the polarization-maintaining direction is obtained.

2 to 4 show other embodiments.

FIG. 2 is a perspective view of an optical fiber, FIG. 3 is a front view showing the manufacturing process of the optical fiber, and FIG. 4 is a front view showing the manufacturing process of the optical fiber array.

In the optical fiber 1 shown in this embodiment, the posture-maintaining protrusion 2 formed on the outer peripheral surface of the optical fiber 1 has a substantially triangular cross-sectional shape. As shown in FIG. 3, this optical fiber is manufactured by using a Si substrate 4 in which a triangular groove 4b is formed.
It can be produced by the same process as (C).

By repeating the same process, a large number of optical fibers 1 having ridges 2 integrally formed as shown in FIG. 2 are obtained.

It goes without saying that the relationship between the polarization maintaining direction of the optical fiber 1 and the protrusion 2 is the same for all optical fibers. The protrusions 2 may be provided with an appropriate length.

Next, as shown in FIG. 4, a Si substrate 8 is prepared in which V grooves 88 are formed at regular intervals. By arranging the optical fibers 1 so that the protrusions 2 of the optical fibers 1 fit within these V-grooves a, and fixing the optical fibers 1 and the Si substrate 8 with adhesive or the like, polarization-maintaining optical fibers and The array is completed.

[Brief explanation of the drawing]

FIGS. 1(A) to 1(E) show optical fibers according to the present invention.
It shows the manufacturing process of the array. Figure 2 is a perspective view showing another example of the optical fiber, Figure 3 is a front view showing the manufacturing process of the optical fiber shown in Figure 2, and Figure 4 is a front view showing the manufacturing process of the optical fiber array. be. 1...Optical fiber. 2... Protrusions for maintaining posture. 4.8...Si substrate. 4a...concave groove. 7...LiNb0i substrate. 7a...Retaining groove. 8a...V groove. that's all

Claims (8)

[Claims] (1) An optical fiber in which a posture-maintaining protrusion with a cross section other than circular is formed along the longitudinal direction on the outer peripheral surface. (2) the cross section of the posture maintaining protrusion has a corner;
The optical fiber according to claim (1). (3) Prepare a mold with grooves for forming posture-maintaining protrusions, inject a liquid material that hardens by energy irradiation between the grooves of the mold and the optical fiber, and irradiate it with energy. A method of manufacturing an optical fiber, comprising integrally forming a posture-maintaining protrusion on the optical fiber by curing the liquid material, and then separating the optical fiber from a mold. (4) A block in which a plurality of optical fibers each having protrusions for maintaining posture with a cross section other than circular are formed along the longitudinal direction on the outer peripheral surface, and a concave portion suitable for holding the optical fibers having the protrusions. an optical fiber array arranged in a line and fixed within the recess of the. (5) The optical fiber array according to claim (4), wherein a plurality of optical fibers are housed in one recess. (6) The optical fiber array according to claim 4, wherein a plurality of recesses are arranged in a line in the block, and each recess accommodates one optical fiber. (7) Create a plurality of optical fibers each having posture-maintaining protrusions along the longitudinal direction on the outer peripheral surface, form a recess suitable for holding the optical fiber having the protrusions on the block, and A method for manufacturing an optical fiber array, comprising arranging and fixing optical fibers having the above-mentioned protrusions in a line in a recess. (8) Injecting a liquid material that hardens by energy irradiation between the groove of the mold having a groove for forming a posture-maintaining protrusion and the optical fiber held opposite to the groove; Apply energy to harden the liquid material, and then
Claim (1) wherein an optical fiber having an integrally formed posture-maintaining protrusion is produced by separating the optical fiber from a mold.
7) The method for manufacturing an optical fiber array according to item 7).